Production equipment of an easily polymerizable compound such as (meth)acrylic acid or (meth)acrylate employs column equipment such as a distillation column for crude (meth)acrylic acid or crude (meth)acrylate or a decomposition reaction column for recovering (meth)acrylic acid or the like by decomposing a high boiling point substance. In such column equipment, part of a column bottom liquid introduced into a reboiler and heated therein may be returned to the column. In order to return a liquid containing an easily polymerizable compound to the column from the reboiler, the column may be provided with: a nozzle for supplying the heated liquid to the column from an opening part on a side wall of the column; an impingement plate for preventing scattering of the liquid to a supply direction; and a top plate for preventing upward scattering of the liquid.
In column equipment having such a structure, a liquid containing an easily polymerizable compound accumulates on a top face of the top plate owing to: supply from the side wall of the column; adhesion or dropping of droplets from above the top plate; and the like. The accumulated liquid is heated by a liquid or gas heated in a reboiler and may form a polymerized product.
As a countermeasure to formation of the polymerized product, a method involving providing at least one hole on a top plate for preventing accumulation of the liquid and allowing the liquid on the top plate to fall may be employed. However, a liquid or gas heated in a reboiler passes through this hole, and thus-caused resistance prevents sufficient falling of the liquid on the top plate. Provision of many holes for the purpose of sufficient falling of the liquid allows the liquid or gas heated in a reboiler to pass through the holes. Thus, the purpose for providing the top plate (to suppress upward flow of the liquid or gas heated in a reboiler with the top plate) cannot be sufficiently attained.